Underwater breathing apparatus



July 14, 1959 D. B. ROSE v UNDERWATER BREATHING APPARATUS s Sheets-Sheet 1 Filed April 3, 1957 4 2 .|||l a z a 0 m 22 Z 9 w 2M 6 a 2 mmvrox. pupa-y B. ease BY W2 7" 7 A I'TOEA/f K? July'14, 1959 D. B. ROSE 2,394,505

UNDERWATER BREATHING APPARATUS Filed April 5, 1957 T 3 Sheets-Sheet 2 I I a I INVEN TOR.

DUDLEY 8. E 5

BY %A,/?, ///A @/M 3 112mm ATI'OE/VEYS July 14, 1959 D. B. ROSE UNDERWATER BREATH ING APPARATUS 5 She ets-Sheet 3 Filed April, 3. 1957 INVENTOR. DUDLEY B. E055 United States Patent UNDERWATER BREATHING APPARATUS Dudley B. Rose, Madison, Ohio Application April 3, 1957, Serial No. 650,520 4 Claims. 01. 128-142 This invention relates to self-contained underwater breathing apparatus.

An object of the present invention is to provide a self-contained underwater breathing apparatus which operates on the demand principle with a minimum of eflort required for both inhalation and exhalation.

Another object of the present invention is to provide a self-contained breathing apparatus having a diaphragm actuated inhalation demand valve and an exhalation valve mounted in a common body which is closely associated with the mouthpiece of the apparatus whereby the external hydrostatic pressure on the diaphragm and the exhalation valve is the same as the internal pressure in the mouthpiece due to their relative location thereby eliminating all differential hydrostatic head pressures and subjecting the mouth of the user to the same internal and external hydrostaticpressure, when in use, thereby permitting relatively effortless breathing by the user of the apparatus.

Still another object of the present invention is to provide a novel breathing apparatus which operates on the demand principle and requires but ,a single small durable medium pressure conduit between the source of air or other fluid and the breathing apparatus which is effective in eliminating mouthpiece pull due to hose buoyancy, water-drag due to hose bulk and corrugations and is less vulnerable to hosefouling, snagging and puncturing. p I

A further object of the present invention is toprovide a novel breathing apparatus having a diaphragm actuated demand valve and an exhalation valve' mounted in a housing closely associated with a mouthpiece, wherein the volume of said housing is so small that substantially all breath is expelled at each exhalation and there being little or no building up of carbon dioxide and re-breathing it during inhalation. I

Still another object of the present invention is to provide a novel breathing apparatus having a diaphragm actuated demand valve and an exhalation valve provided in'the zone of the mouthpiece of. the :breathing apparatus wherein three-way equalization of essential pressures, namely pressure at demand valve diaphragm, pressure at exhalation valve, and pressure at mouth, permits uniform elfortless breathing at any depth or position of the user due to the elimination of differential hydraulic head pressure between the above locations.

Another .object of the present invention is to provide a novel breathing apparatus 'which operates on the demand principle and is characterized by its structural simplicity, the ease of assembly of its parts, its strong and sturdy nature and its low manufacturing cost. Other features of this invention reside in the arrangement and design of the parts for carrying outtheir appropriate functions. I I r Further objects of the present invention and certain practical advantages will be referred to in or will'be evident from the following. description of two: embodiinvention is denoted by the appended claims.

2,894,506 Patented July 14,

ments of the invention, as illustrated in the accompanying drawings in which: I v

. Fig. 1 is a perspective view of the mouthpiece'and its associated valve housing shown connected through a single conduit and a suitable control valve to a source of air or other fluid. J I

Fig} 2 is a vertical sectional view of the mouthpiece and valve housing of the present invention and showing the inhalation or demand valve in a closed position.

Fig. 3 is a vertical sectional view of the present invention similar to that of Fig. 2, but showing the diaphragm expanded and the inhalation or demand valve in an open position. i

Fig. 4 is a top view of the diaphragm cover which serves to protect the diaphragm against foreign objects and further to clamp and seal the diaphragm to the valve housing of the present device.

Fig. 5 is a vertical transverse sectional view taken along the plane ofline 55 of Fig. 3 and looking toward the exhalation valve of the present device;

Fig. 6 is a front elevational view of another embodiment of the present invention employing a circular housing and diaphragm. I

Fig. 7 is a vertical section view of the breathing device shown in Fig.. 6 taken along the plane of line 7-7' of Fig. 6.

Fig- 8 is a top plan view of the diaphragm used in connection. with the embodimentof the present invention disclosed in'Fig. 6..

Fig. 9 is a vertical cross-sectional view taken along the plane of line 99 of Fig. 8. Fig- 1.0 is a vertical cross-sectional view similar to that inFig. 7 but showing the diaphragm flexed inwardly and the demand or inhalation valve in an open position, and

Fig. 11 is an enlarged fragmentary sectional view of the demand valve disclosed in the embodiment of Figs. 6 through 10.

Before describing. in detail the herein disclosed embodiments of the invention, it is to be understoodthatthe present invention not limited to the structural details or the'particular arrangementv of parts herein shown as devices embodying the present inventionmay take other forms. It. alsois to be understood that the phraseology and terminology herein used are for purposes of description and .not of limitation, as the scope of the present Referring now to Fig. 1,. the breathing apparatus in general will beseen toinclude a housing 10-.having a chamber for adiaphragm and an exhalation and inhalation valve. A, mouthpiece 11 is closely associated with the housing and-has a single medium pressure hose 12 communicatingbetween the inhalation valve of the mouthpiece and a source-.of air or other fluid container 13. The air container 13 is provided with a suitable manually operable control valve14 by which thepressure inthe hose may be readily and accurately regulated. 1 1

It. will be understood that the air container 13 is normally provided with-a suitable harness,-not--herein shown, whereby it may be supported on the body of a person using the apparatus. The air source here C0111? prises a container or bottle of cylindrical form 13. and-a pressure control valve 14 which may be of any" suitable form and its sole purpose is to control the pressurein the connecting hose or conduit 12. The pressure reducing valve is attached to the tank by means of a-suitable yoke attachmcntlS.

1 With reference now toFigs. 2 and 3 the novel selfcontained underwater breathing apparatus comprises a mouthpiece 11 preferably constructed of a soft rubber or plastic material: and a main body or housing 10 preferably constructed of a durable metal or hard plastic material which will resist wear and breakage. The central portion of the housing is substantially rectangular in form ha'ving rounded ends and forms a chamber 16, as seen in Figs. 2 and 3. The chamber 16 is open at its front or top end as seen in Figs. 2 and 3 and is provided with suitable ports 17 and 18 which communicate through the mouthpiece with the mouth of the user, when in use. The right end of the housing 10 is provided with a hollow cylindrical shaped extension 10a which contains an inhalation or demand valve. The cylindrical extension 10a is threaded internally at 19 and threadedly receives a tubular socket 20 in its outer end. A tubular member 21 is adapted to be slipped into freely within the tubular socket 20. An O-ring seal 23 I is carried within a suitable groove provided in the tubular member 21 and engages the inner surface of the tubular socket so as to provide a seal between the member 21 and the socket 20. An elbow fitting 24 threadedly engages the tubular member 21 adjacent its outermost end in such a manner that the tubular member 21 rotates in response to the movement of the elbow 'fitting 24. A suitable nipple 25, as seen in Fig. 1, is secured to the elbow 24 .and is adapted to engage the end of the flexible hose 12 with this construction therefore, it will be realized that the elbow 24 will swing with the tubular member 21 and thereby follow the movement ofvthe hose 12 and/ or the housing 10 such that said hose does not become crimped or otherwise fouled, thus preventing any interruption in a fluid input flow from the container 13.

g The tubular member 20 is provided with an inlet fluid port or passage 26-at its innermost end which communicates fluid between the hose 12 and the chamber 16 of the housing 10. A valve seat 27 is formed on the upstream face of the port 26 and is adapted to be engaged by a tilting. demand valve body member 28 for opening and closing the inlet fluid port 26. The demand valve body 28 is provided with a valve stem 29 which extends in axial alignment through the center of port 26 so as to permit the valve stem 29 and its associated valve body 28 to be slightly tilted. The valve stem 29 projects into the chamber 16 and is adapted to be engaged by the inner end of a flexible diaphragm 30 provided in the chamber 16 and which hasits outer side exposed to exterior hydrostatic pressure. Upon inhalation the chamber 16 is exhausted of its fluid so as to reduce the pressure therein and permit the diaphragm to be forced inwardly by the exterior hydrostatic pressure, against the valve stem 29 which in turn tilts the demand valve body 28 into an open position, as shown in Fig. 3, thereby permitting the fluid which is under pressure from the reservoir or container 13 to flow through the-flexible conduit 12 into the chamber 16, hence through ports 17 and 18, to the person being served with the fluid. When inhalation ceases the demand valve is moved back into a closed position by a biasing spring 31 associated with the valve stem 29. The biasing spring 31 rests on a base provided by the inner end of the tubular member 21 and tapers toward its outer end until its outermost coil is in close contact with the valve stem 29. The spring 31 normally urges the stem 29 and valve body 28 into'a port closing position.

A baflie 32 extends'downwardly, as seen in Figs. 2 and- 3, toward the valve stem 29 so as to provide a guide or abutment for the valve stem and prohibit the valve stem from moving in an upward direction. The baflie 32 serves the additional function of diverting the incoming fluid flow away from the diaphragm 30 and towardthe ports 17 and 18. xz-Thediaphragm 30 consists of a hollow bellows which may e xpand andcontact due to its corrugated surface 4 consisting of alternate ridges 33 and valleys 34. The outer peripheral contour of the diaphragm is generally rectangular, the two longer sides being parallel to one another and having rounded end portions. The diaphragm is hollow in the center and open at its top while the bottom thereof is completely closed. The bottom is preferably provided with a metal plate 35 having a depending lug 36 which engages the valve stem 29. The diaphragm 30 is entirely contained within the chamber 16 and is adapted to be sealingly secured at its upper end to the housing 10. As seen in Figs. 2 and 3, the housing 10 is provided with a recessed shoulder 37 which extends completely around its periphery. A diaphragm cover member 38 is adapted to have the edge 30a of the open end of the diaphragm slip snugly around its outer edges in such a manner that the diaphragm cover 38, which is adapted to fit snugly within the recessed shoulder 37, snugly compresses the upper edge of the diaphragm between its outer edge and the recessed shoulder 37 so as to provide a water-tight seal between the diaphragm and housing 10. The diaphragm cover 38 is preferably constructed of metal or suitable plastic material and is provided with a plurality of spaced apertures 39. The diaphragm cover protects the diaphragm 30 against damage from foreign objects but still allows the Water to pass through its apertures without restriction and subject the diaphragm to exterior hydrostatic pressure. It further acts as a clamping plate to seal the diaphragm 30 tightly to the body 10 and serves as a stop to limit the outward movement of the diaphragm 30. i

The metal plate 35 at the bottom ofthe diaphragm also aids in adding rigidity to the bottom of the diaphragm and causes the diaphragm to expand and contract in a uniform manner. It also functions to exert pressure upon the valve stem 29 at but a single point, that being at lug 36.

The diaphragm 30 normally extends downwardly into the chamber 16 under exterior hydrostatic pressure to an extent wherein it just abuts the valve stem 29, as seen in Fig. 2. Upon inhalation by the user the diaphragm 30 is expanded inwardly due to the decreased pressure in chamber 16 which permits the exterior hydrostatic pressure to push the diaphragm inwardly against the valve stem so as to tilt the valve stem 29 which in turn tilts the demand valve body 28 into a port open position. During inhalation the diaphragm 30 expands from its normal position, as seen in Fig. 2, to that as shown in Fig. 3. As soon as the user ceases to inhale or upon exhalation which increases the pressurein chamber16, the diaphragm 30 will return to its position, as illustrated in Fig. 2, whereby the inlet port 26'is immediately closed. It will 'be understood that this particular structure is designed to furnish necessary fluid to the diver on demand with a minimum of effort required for both inhalation and exhalation. The external hydrostatic pressure onv the diaphragm 30 aids the diver during inhalation in overcoming the slight pressure exerted upon the valve body 28 by the fluid from container 13.

Valve means are provided whereby the exhaled fluid may be discharged from the device with substantially no resistance. This is accomplished by means of an exhaust or exhalation valve which is located in substantially the same zone and subject to the same exterior hydrostatic pressure as that of diaphragm 30 and the exterior por' tions of the mouth of the user. The exhalation valve is located in a hollow cylindrical extension 10b located at the left of the housing 10 as seen in Figs. 2 and 3. A fluid outlet port 40 is provided at the junction of the cylindrical extension 10b and the chamber 16 by means of a pair of crossing spoke-like members 41 and 42 having a hub 43 at their intersection. The exhalation valve unit itself consists of a relatively thin circular disc 44 preferably constructed of rubber or other flexible material and having at the center thereof an outwardly proiecting pqrtiqnlS th n n ged e p rtion adapted to be engaged within an;aper-ture--provi ded in thehub-43t The outr peripheral edge of the flexible valve diso- 44 is normally; sealing engagement with a; valve seat; 46 provided-on'the-downstrearn face of the outlet port-40. The cross; spokes- 41 and 42 provide additional support for the flexible valve disc-44' duringinhalation. It will understoodthat-only during exhalation or increased chamber- 1;6 pressure does'the outer peripheral edge of valve'disc 44-ilex outwardly or-lift away'f romvalve'seat 46; thereby-openi ng outlet' port 4(l-to permit the" exhaust fiuidsto be delivered to the exterior'of thedevice; During inhalation; the flexible valve disc 44 is merely drawn into closer sealing'cOntact with the valve seat 46' and the-cross; spoke members 41" and* 42.

A suitable filter 48 preferably constructed of porous metal bronze. sponge rubberor. foam plastic is provided in; the" cylindrical extension b; downstream of the valve 44' andperformsythefunction of protecting the valve 44 as well as filtering; the exhaust fluids.

mouthpiece 11" provides means for holding the s'elf-containedunit inthemouth of. the user and at the same time sealing outall water. It is to be understood thatthe curved arcuate portion 50'i s ad'aptedto be placed in the mouth between the teethand theinner lips While thepnojecting portions 51 extend between the teeth and are'adaptedl to be grasped, by the teethof the user for rete ti h he hhet tu T e m t p 0 is a so hr d e i e pa r of s ac d. oo s or ring. memb s 5 hdi which a a p d? o; e r the bo y een hf s 1 2. end 3* ahdir eih he di p ra m eo er 8-ihhos t oh- A. eta ne n nds. et eehthe o loeh member 5 and 53; n maintain h spa in e ween. t e loo s. to pr e them from h omihgeee le he ht l nl e l' remth bo y 0"- It should now be apparent that the invention has two W iQEeSR srshit 'e litetes h ease of breathing wh h. s me leh ss bl by loeet ha the d ehhteg h'and eezhehs n h ome ne a th mou h of he user. ther b p e eh h i f rent a h dr st tie. he Pressu e herebet e n nd u ieet s the mouth of he been to. he same nt r al and. exte nal hyd o tatie p e sure when. i use her b perm t i re ativ l effortleSS le th hshy t e se f aid pr re h t S c nd, t e nh t hs s. extr mely tem es wi h th em nts. there- Qf Pro i ng a lhr tyo f hot ohs. Thus,.. y equalizihgj he three esse ti l n su es; namely the p e ur at he. i nhregr ..t e p essu e n th mou h a hem ssh e at hei xh a ioh lve. i becomes Possible, topmid uniform eitort e sbr at ngat any d pt Unequ Press-ti es... du to a d fie en e o d p between th e hembets eeu e a d f eren ia hydrostatic hea P es ure whichmust: be overcome by the user while breathing. "For n t t -pre ure. equ l n both th iaph gm: nd e at val e sho fstble n t e zon of he. m nth "me as s fQ h h hepteseh h e t hy Pr yislle the v rious. 'QQI lPQherlts, as he etof re describe adiaoent the mouth iti'spossible to assure constant. equal.- izedpresshre a any deg h d unde all e htlit ons he e: PhQY Qi I11? h $h etf rtle s breathing possible;

he sin l me umnresshre o e o condu t .2 is more urable. ari .v less, vulnerable t hose damage and allows more. freedom t an t e ov zed' hoses a used la he est.v T e p es n in le h e imina e mouth- Pieqe 21 .1 thi o o o hey. and. ter drag? cau ed: y ho u s and eorru tions It is. o. es hlhehe le. t hose ou n sn puncturing, Ihq 11956 connection permits self-positioning"of the; mouthpiece ion most comfort and eliminates cramping; in; the neck and jawsof the diver- Due=to.the= small size of the chamber 16 there isno danger. of building up astoreof carbon dioxide and rebreathing: it sincesubstantially all breath is expelled at each exhalation; Through the provision of the present invention, wherein all-breathing is done through a mouthpiece held in-the mouth of the user; all-faoe niashnrouthpiece andhosecaivity rebreathing-has-been-eliminated; Tests have proven that the pressure onthe faee is the only noticeable foree to'be overcome inunderwater breathing. The present design has simplified the process ofmaintaining the; same internal and external pressure on the; face of the userby locating the diaphragm and exhalation valve in themouthpiece The pressurejsensitive area as determined; these testsproved that; the present unit works equally well in all positions of the swimmer, Prior devices 'of this type; do; not;;maii1tain the demand-- valve controlling; diaphragm; and thepresjsure sensitive face area at the same, pressure'head,"but permitted a diiference to exist in the} internal and we ternal pressure on the face which-had to be overcome by the'exertion of a muscular forge by, the. swimmer;

In Figs. 7' through 11 I have shownstillanother, em-

bodiment; of thepresentinvention. The principles employed in this embodiment are similar to those of the firstembodiment of the invention, however; the structure has beenslightly modified; as explainedhereinafterr jTh G main body or housing 60' of the device is ciroular in as seen in Figs. 6 and 7. The diaphragm 61 is con,- ed of a uit ble thin. fle b ma erial... sash rubber. d cons of e." in le. unb oken dish he h eh arwete e P n fil hieh m ltes e d aph a m h ore flexible. nt. di hrag isgenere y e e l'er ln sheoe and m s bs nt ally a wel o t e ehemb t 63 ap a m s et ned by. means. f e e r ular: oo r me e hi h hreee edly n a es th body port 11 e 65. t v s ur the oute neriphle aled .95 aphra be e n the b y' e land o er 4, e ..'se.eh F gs nd .0- I

he nd rsu eee of: th dienhr gn 61' is named i h a. thin. s nr t hs Pla e 7 R f$ Q Yl' g k fil qll r n s ie hi hv dds i i i y t the. than, man and hi toe t se he a hra m. to move a o tth zone 6.2 'whieh s. ra ally beyohd' he outer. eire htfierential edge of. the Plate he eov 6.1 s appl ed. t the bo y 6!) ove heouter Peripheral edge 66 of he e leh ra rtiv 1. e d. sn o idetl w th a plurality of p ed op in s tonermltt exterior hydr s at pres ure to... a on the out r surface o d aphragm 6.1-. The COverfllSO a ts onroree he d aph a m again t o eign. ob ec s,

Th den hdi ely ody 7.1.has bee so ewhatmodi e and nc udes. a seat. enga ing-me ber 7 wh is a apted to en age. the a ve. eat a seen. in l1. The seat engaging, m mber is. r gidly se ured i he al ody- 1 ehs 'no itions the valve. body a naced istenee fr th the val sea 1 h eat en a in membe '12. is r gid y seem d 9. the. valvebody. 7.1 lld posit on he val e b dy 71.. a spa ed d steheefm h he valve seat 73. The seat engaging member is concenttic to. the va ody member an h s. a th subs aht y maller han the. alve. body. m mber. a d 5 1s sl h ly eate ha the inl t port The se t ngeg n hiehh be 7 tilts ou ts te p riphery in resp iis' o moy e men o he. iap ragm 61 nd. the by er eas y opens th inlet port 74., as. shown in. Fig. r The seat eh gag; n member 72. a in a smal r rea. than. th valve bo y e ber 71 s u j cted to e s pre ure. bye air nose 7 than the. valv body heref r i re: quires less force from the diaphragm and valve stern.75 t ope h inlet port 74.- us, upo n al t n y the. user, the pressure in chamber 63fdecreases and, the ex or yd ic pr u e forces d a h a m 61 nrd y of cham er 6 and ses the al e stern,- 5, which is preferably merely in bearing contaet but-may b pivotally secured by any. suitable means to the plate 70 to tilt the valve body 71 about a pivot point defined by the outer circumferential edge 76 of the member 72 After the inlet porthas beenopened by the. Seat engaging mernber 72,, pivoting about its. outer edge 76,. it; will. be readily understood that a transition occurs wherein the outer circumferential edge 71a of valve body 71 becomes the pivot pointthereby causing the inlet port to be opened much faster and to a greater extent per unit deflection of the valve stem 75 than would be the case if pivoting continued about the point 76 of seat engaging member 72. This is true because the outer circumferential edge 71a is located radially farther away from the valve stem 75 than the outer circumferential edge 76 of the seat engaging member 72. Thus, only a slight movement in the diaphragm 61 is required to provide a somewhat faster and more extensive opening in the inlet port than was possible in the'first embodiment of the invention. Coil spring 95 normally biases the valve stem 75 into a valve closed position.

A hollow cup like member 99 is secured to the lower surface of plate 70 with its open end disposed toward the interior of chamber 63. The end of valve stem 75 preferably rests in the cup as shown in Figs. 7 and 10. As the diaphragm deflects inwardly' of the chamber 63, it Willbe readily understood that the outer circumferential edge 99a of the cup will engage the valve stem and thereby shorten the lever arm and cause the valve stem to tilt at a faster rate thereby more quickly opening the inlet port 74.

A universal joint is provided for the connection between the apparatus and the flexible hose 78 which communicates, with a fluid source. The universal joint is provided by. a ball 80 which is movably secured to a cylindrical extension 60a of the housing 60 by means of a retainer ring 81 which threadedly engages the outer surface of thecylindrical extension 80a at 82. The ring member 81 has an inwardly extending rim 82 adjacent its outer end which provides a circular opening having a smaller diameter than to greatest diameter of the ball 80 and thereby retains the ball within the cap 81.- An ring ,83 is providedto seal the ball and cap against leaks. The ball 80' is provided withan elongated portion 84 and a bore 85 which extends through the ball and also through the elongated portion thereof to provide communication between the inlet port 74 and the flexible hose 78; '1"he' ,l1ose78 slipsover and snugly engages the elongated portion 84 of vball 80. The mouthpiece 88, which is constructed substantially the same as that shown in Fig. l with the exception of the spaced loops 52 and 53 which are eliminated in the present embodimentjbecause of the cover 64, threadedly engagesthe body member 60 and the'mouthpiece is secured'to the bodyby means of an outstanding flange 90 on body 60. Ports 96 and 97 communicate between chamber 63 and the mouth of the user.

) An exhaust or exhalation valve 92 and a filter 93 are provided in the extension 60b of the housing 60 in much the same manner as shown in the first embodiment and in substantially the same zone as the demand or valve body 71 and thediaphragm 6 1.

"The"enla.rged circular diaphragm 61 is somewhat quicker to respond to decreased or increased chamber pressure due to inhalation and exhalation respectively and'thereby when coupled with the high flow, quick opening demand valve body 71 provides a very eflicient device The universal coupling provided by the ball and socket joint also makes the device very easy to maneuver.

In all other. ways the second embodiment of the invention is identical'in operation and function to that disclosed in Fig. 1.

In view of the foregoing description taken in conjunction with the accompanying drawings, it is believed that a clear understanding of the construction, operation and advantages of the device will be quite apparent to those skilled in this art.

Having thus described my invention and illustrated its use, what I claim as new and desire to secure by Letters Patent is: I

' 1.; breathing apparatus comprising in combination agas container, a housing having a chamber and a mouthpiece integrally associated therewith and adapted to be engaged by the mouth of the user, said mouthpiece having an opening communicating between said chamber and the mouth of the user, a single conduit connected between said housing and said gas container, a gas inlet port in said housing communicating with said chamber and said conduit, a demand valve controlling said gas inlet port, a substantially rectangular diaphragm in said chamber having one side thereof exposed to exterior hydrostatic pressure and movable in response to a decrease in pressure in said chamber, said diaphragm having corrugated sidewalls permitting said diaphragm to expand and contract in a bellow-like manner, means operatively associated between said diaphragm and said demand valve causing opening movement of said demand valve in response to expanding movement of said diaphragm, a gas outlet port in said housing in communication with said chamber, anexhaust valve controlling said gas outlet port, said exhaust valve adapted to open in response to an increase in pressure in said chamber, said external hydrostatic pressure being insufficient to cause said diaphragm to open said demand valve, reduced chamber pressure permitting said external hydrostatic pressure to expand said diaphragm thereby causing said demand valve to open, increased chamber pressure causing said diaphragm to contract thereby closing said demand valve and opening said exhaust valve, said chamber pressure being increased or decreased in response to exhalation and inhalation'respectively by the-user, said diaphragm and said exhaustvalvebeing. located in the same zone as the mouth of the user, thereby preventing 'diiferential hydrostatic head pressure therebetween and subjecting the mouth of the user to the same internal and external hydrostatic pressure when in. use thereby permitting relatively effortless breathing by the user of said apparatus.

2. A breathing apparatus comprising a housing,} a mouthpiece integrally associated with said housing and adapted to be engaged within the mouth of the user, a chamber in said housing and disposed in the same zone as said mouthpiece when in use, said mouthpiece having an opening communicating with said chamber. and the mouth of the user, a demand valve in said housing controlling the flow of gas from a suitable source into said chamber, a substantially rectangular diaphragm in said chamber, said diaphragm having corrugated sidewalls permitting said diaphragm to expand and contract, said diaphragm having a closed bottom and an open top, said top having its peripheral edges secured to the edges of an opening in the side wall of said housing whereby one surface of said diaphragm is exposed to exterior'hydrostatic pressure, a perforated cover for said opening in the side wall of said housing supporting said diaphragm in sealing engagement with said housing, said diaphragm movable in response to pressure changes in said chamber, means operatively associated between said diaphragm and said demand valve causing opening and closing movement of said demand valve in response to movement of said diaphragm, an exhaust valve in said housing controlling the flow of gas out of said chamber in response to pressure changes in said chamber, said chamber pressure being increased or decreased in response to exhalation and inhalation by the user, said diaphragm and said exhaust valve being located in the same zone as the mouth of the user, thereby preventing differential hydrostatic head pressure therebetween and subjecting the mouth of the user to the same internal and external hydrostatic pressure when in use thereby permitting relatively effortless breathing by the user of said apparatus.

3. A breathing apparatus comprising a housing, a mouthpiece associated with said housing and adapted to be engaged within the mouth of the user, a chamber in said housing and disposed in the same zone as said mouthpiece when in use, said mouthpiece having an opening communicating with said chamber and the mouth gre ses of the user, a demand valve in said housing controlling the flow of gas from a suitable source into said chamber, a substantially rectangular diaphragm in said chamber, said diaphragm having corrugated side walls permitting said diaphragm to expand and contract, said diaphragm having a closed bottom and an open top, said top having its peripheral edges secured to the edges of an opening in the side wall of said housing whereby one surface of said diaphragm is exposed to exterior hydrostatic pressure, said diaphragm movable in response to pressure changes in said chamber, means operatively associated between said diaphragm and said demand valve causing opening and closing movement of said demand valve in response to movement of said diaphragm, an exhaust valve in said housing controlling the flow of gas out of said chamber in response to pressure changes in said chamber, said chamber pressure being increased or decreased in response to exhalation and inhalation by the user, said diaphragm and said exhaust valve being located in the same zone as the mouth of the user, thereby preventing difierential hydrostatic head pressure therebetween and subjecting the mouth of the user to the same internal and external hydrostatic pressure when in use thereby permitting relatively efi'ortless breathing by the user of said apparatus.

4. A breathing apparatus comprising in combination a. gas container, a housing having a chamber and a mouthpiece integrally associated therewith and adapted to be engaged by the mouth of the user, said mouthpiece having an opening communicating between said chamber and the mouth of the user, an inlet member swingably mounted in said housing, a single conduit connected between said inlet member and said gas container, said inlet member being swingably movable with the movement of said conduit and/or housing to thus prevent a crimping of said conduit, a gas inlet port in said inlet 19 member communicating with said chamber and said conduit, a demand valve controlling said gas inlet port, a substantially rectangular diaphragm in said chamber having one side thereof exposed to exterior hydrostatic pressure and movable in response to a decrease in pressure in said chamber, said diaphragm having corrugated sidewalls permitting said diaphragm to expand and contract in a bellows-like manner, means operatively asso-' ciated between said diaphragm and said demand valve causing opening movement of said demand valve in response to expanding movement of said diaphragm, a gas outlet port in said housing in communication with said chamber, an exhaust valve controlling said gas outlet port, said exhaust valve adapted to Open in response to an increase in pressure in said chamber, said external hydrostatic pressure being insufiicient to cause said dia phragm to open said demand valve, reduced chamber pressure permitting said external hydrostatic pressure to expand said diaphragm thereby causing said demand valve to open, increased chamber pnessure causing said diaphragm to contract thereby closing said demand valve and opening said exhaust valve, said chamber pressure being increased or decreased in response to exhalation and inhalation respectively by the user, said diaphragm and said exhaust valve being located in the same zone as the mouth of the user, thereby preventing diflerential hydrostatic head pressure therebetween and subjecting the mouth of the user to the same internal and external hydrostatic pressure when in use thereby permitting relatively efi'ortless breathing by the user of said apparatus.

References Cited in the file of this patent UNITED STATES PATENTS Meidenbauer Dec. 27, 1955 

